The invention relates to a connecting device for connecting a wiper blade to a wiper arm.
A connecting device of the generic kind is known from the German patent publication DE 103 47 637 A1. A wiper blade of flat beam design is connected via said connecting device to a wiper arm in an articulated manner. The wiper blade comprises a wiper strip, in the longitudinal grooves of which two spring rails are laterally inserted, which serve as a support element and to which a connecting element in the form of a sheet metal claw is fastened. The connecting element comprises a central web which extends in the longitudinal direction of the wiper blade and which bears a hinge shaft that runs transversally thereto. Hubs of an adapter are mounted on the hinge shaft on both sides of the central web, wherein said hubs are arranged in spring tongues. Said hubs form laterally flexible parts of the side walls of the adapter. The spring tongues are separated from the side walls by gaps except for one side which faces away from the wiper strip.
Besides the side walls, which are connected to one another by means of a top wall, the adapter comprises a front end wall, which has a projection in the direction of the side walls and the top wall. Said projection provides contact surfaces for an end edge of a joining element which is integrally formed on a wiper arm. A connecting profile for a spoiler part is furthermore provided in the front end wall, said spoiler part being fastened to the spring rails and covering the wiper blade on the side facing away from the wiper lip. A spoiler part is disposed in each case on both sides of the connecting element in the longitudinal direction.
In order to stiffen the side walls of the adapter, numerous transverse walls and stiffening ribs are provided between said side walls. In addition, these serve to laterally guide the adapter along the longitudinal web of the connecting element.
During assembly, the joining element is pushed over the adapter transversely with respect to the longitudinal direction of said adapter and in the direction of the wiper strip until the guide rails engage with detent lugs in spring tongues along the lower longitudinal edges of the side walls of said joining element. In the assembled state, the end sides of the guide rails facing towards the free end of the wiper blade rest against guide rails of the adapter, which catch below the side walls of said joining element. Furthermore, the end edge of said joining element rests against the projection of the front end wall of the adapter, which has an undercut in the region of the adjacent guide rail, which fits to the front end edge of said joining element.
The adapter comprises in the top wall thereof a spring tongue having a push button facing outwards. The spring tongue extends in the longitudinal direction of the wiper blade and is connected to the top wall at the side facing the front end wall Apart from this, said spring tongue is furthermore separated from said top wall by a gap. In the fitted state the push button latches into a matching opening in the joining element and thereby secures the fitted position of the adapter in the longitudinal direction with respect to the joining element.
The wiper blade can also be mounted to the wiper arm in the longitudinal direction by the joining element being pushed from the rear end wall of the adapter over the same until the push button latches into the matching opening in said joining element. In so doing, the guide rails of said joining element latch under the detent hooks on the lateral spring tongues of the adapter.
A similar connecting device is known from the German patent publication DE 60 2004 010 644, in which the spring tongue is fastened to the top wall of the adapter on the side thereof facing the rear wall. The rear wall itself is reduced to a transverse web so that the connecting cross sections are very small with respect to the side walls.